Methods and devices for the cooling of aqueous liquids according to the evaporation principle are known. By the suctioning off of water vapor, an aqueous liquid is brought to evaporation and thereby cooled. In order to cool aqueous liquids to temperatures close to the solidification point, considerable water vapor volumes must be suctioned off.
Although direct evaporation makes possible a very rapid and gentle cooling, it has been possible up to now to implement it economically only in a few application cases.
Adsorption devices are devices in which a solid sorption agent sorbs a second agent, the working agent, which boils at lower temperatures, as a vapor, with the release of heat (sorption phase). The working agent thereby evaporates in an evaporator with heat absorption. After the sorption agent is saturated, it can once again be desorbed by the supply of heat at a higher temperature (desorption phase). The working agent thereby evaporates from the adsorption agent. The working agent vapor can be reliquefied and then re-evaporated.
Adsorption devices for cooling with solid sorption agents are known from EP 0 368 111 and DE-OS 34 25 419. Sorption agent containers filled with sorption agents suction off the working agent vapor that is generated in an evaporator and sorb it with the release of heat. This sorption heat must be removed from the used sorption agent. The cooling devices can be used to cool food and to keep it warm in thermally insulated boxes.
In German Patent DE 4003107, a method for making ice under vacuum with a simultaneous sorption of the outflowing water vapor in a sorption agent is described. An aqueous liquid is thereby solidified in a flanged vacuum-tight icing container.